Process of producing continuous castings of square or circular cross-section



Nov. 18, 1969 TARMANN ET AL 3,478,809

PROCESS OF PRODUCING CONTINUOUS CASTINGS OF SQUARE OR CIRCULAR CROSS-SECTION Filed June '7, 1965 Casfz'ng alien in; 292g lQ/ZS 1% Z 524/50 Erma/m United States Patent US. Cl. 164-82 12 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a method of obtaining square or circular cross-sectioned continuous castings by firstly utilizing a mold having a diamond or oval cross-sectional shape, then hot-forming the resultant casting into a respectively square or circular cross-sectional shape by commensurately shaped rolls.

This invention relates to a process of producing continuous castings of square or circular cross-section, particularly of steel.

In this process, the continuous casting emerging from a mold is moved along a straight or curved path through the so-called after-cooling region and then passes between feeding and straightening rollers, after which it is cut into the desired lengths. Only the skin of the casting solidifies in the mold. The interior of the casting solidifies in the after-cooling region. Contraction causes the solidified skin of the casting to lift from the mold wall. This lifting is highly irregular so that the resulting castings do not have exactly the same cross-sectional shape as the mold. The square-section castings are usually diamond-shaped and the circular-section castings depart from a circular form at various points of their periphery. Small irregularities during teeming are inevitable and give rise to one or more changes of said irregularities in the cross-sectional shape of the resulting castings obtained by one and the same teeming. This results in difiiculties during the conveying of the casting in the feeding or straightening apparatus, particularly if grooved rolls are used therein. In certain subsequent processes, e.g., during piercing to produce tubes, it is desirable to use castings which have exactly uniform crosssectional shapes.

For this reason, it is proposed according to the invention to use molds having a diamond or oval cross-sectional shape for continuous casting in such cases and to shape these diamond or oval castings to squareor circular-section castings, respectively, in a pair of grooved rolls defining a closed pass with the utilization of the residual heat of the casting.

It has been found that the cross-section of castings obtained from molds having "a diamond or oval cross-sectional shape remains extremely uniform throughout the teeming so that it is easy to provide grooved rolls defining such a pass whereby castings having an exactly square.

or circular cross-section are obtained.

Continuous casting installations, in which the resulting castings are shaped by the feed rolls or by additional rolling mills with the utilization of the residual heat of the casting, are known per so. For instance, it has been suggested to roll down flat-section castings to sheet metal gauge, e.g., with the aid of cluster mills, or to divide fiatsection castings having fiat or pro-profiled side faces into a plurality of part castings with the aid of suitably grooved rolls. Contrary to these known proposals, however, the invention is concerned with the shaping of individual castlugs.

I CC.

Referring to the drawings, FIG. 1 is a diagrammatic view illustrating the casting leaving the mold, and

FIG. 2 is a diagrammatic view illustrating the crosssection of the casting upon entering the gauged rollers.

In FIG. 1 it will be noted that a continuous casting 1 emerging from a mold 2 has core 3 thereof in a liquid state and the casting is of diamond cross-sectional shape. The casting 1 is shaped in a closed pass defined by a pair of grooved rolls 4 and the profile of the coacting roll provides a closed pass denoted 5. The cross-section of the casting 1 as it enters the grooved rolls is diamond shaped as indicated by the broken lines and when the casting leaves the rolls it is square in cross-section.

Thus, the invention provides a process of manufacturing continuous castings of square or circular crosssection, especially of steel, in which the continuous casting emerging from the mold is shaped in a closed pass defined by a pair of grooved rolls with the utilization of the residual heat of the casting and is characterized in that the shaping changes the cross-sectional shape of the casting from oval to circular or from diamond to square in a manner known from individual rods.

In continuous casting installations, the feeding means comprise usually one or more pairs of rolls. For this reason, it is a development of the invention to shape with the aid of one of the pairs of rolls which act also as straightening or feeding rolls.

According to the invention, the shaping of the crosssection may be combined with a substantial reduction of the cross-section of the casting and the substantial reduction in cross-section may be assisted by maintaining the casting under tensile stress by succeeding feeding rolls while the casting is being shaped in the closed pass defined by the pair of grooved rollers.

It is another advantage afforded by the invention that a pair of grooved rolls may form a plurality of closed passes disposed one beside the other and shaping the casting to different cross-sections. In this case, the casting may be fed to a selected one of these closed passes so that castings differing in cross-section may be made without the need of changing the mold. The casting is preferably guided between the mold and the shaping rolls by grooved guiding rolls, which conform to the crosssection of the casting and these guiding rolls are, or part of them is, displaced or pivotally moved to guide the casting to a selected pass of the shaping rolls.

What is claimed is:

1. A process of manufacturing continuous castings, said process comprising providing a mold having an oval shaped cross-section; withdrawing from the mold a continuous casting having an oval cross-section, and the longer axis of the cross-section remaining in the same direction as the longer axis of the mold, and then hotforming said continuous casting in a closed pass between and by a pair of cooperating grooved rolls to a circular cross-section, with said hot-forming being effected while said casting still contains sufiicient residual heat from the casting operation to enable said hot-forming.

2. A process as set forth in claim 1, in which said continuous casting consists of steel.

3. A process as set forth in claim 1, in which the crosssectional area of said continuous casting is substantially reduced by said hot-forming; and imparting tensile stress to the said casting by suceeding pairs of feeding rolls while the said casting is being hot-formed.

4. A process as set forth in claim 1, in which said pair of grooved rolls employed for said hot-forming has a plurality of closed passes adapted to impart different cross-sections to said continuous casting, and which crosssections have uniform dimensions in any two directions which are at right angles to each other.

5. A process as set forth in claim 4, in which said casting is guided between said mold and said grooved pair of grooved rolls by grooved guiding rolls, which conform to the cross-section of the continuous casting as it is withdrawn from the mold; and at least part of said guiding rolls is adjusted to guide said continuous casting to a selected pass of said grooved rolls for hot-forming.

6. A process as set forth in claim 5, in which said part of said guiding rolls is pivotally adjusted.

7. A process of manufacturing continuous castings, said process comprising providing a mold having a diamond shaped cross-section; withdrawing from said mold a continuous casting having a diamond cross-section, and the longer diagonal line of the cross-section remaining in the same direction as the longer diagonal line of the mold, and then hot-forming said continuous casting in a closed pass between and by a pair of cooperating grooved rolls to a square cross-section, with said hot-forming being effected While said casting still contains sufficient residual heat from the casting operation to enable said hot-forming.

8. A process as set forth in claim 7 in which said continuous casting consists of steel.

9. A process as set forth in claim 7 in which the crosssectional area of the said continuous casting is substantially reduced by said hot-forming; and imparting tensile stress to said casting by succeeding pairs of feeding rolls while said casting is being hot-formed.

10. A process as set forth in claim 7 in which said pair of grooved rolls employed for said hot-forming has a plurality of closed passes adapted to impart different cross-sections to said continuous casting, and which cross-sections have uniform dimensions in any two directions which are at right angles to each other.

11. A process as set forth in claim 10 in which said casting is guided between said mold and said grooved pair of grooved rolls by grooved guiding rolls, which conform to the cross-section of the continuous casting as it is withdrawn from the mold; and at least part of said guiding rolls is adjusted to guide said continuous casting to a selected pass of said grooved rolls for hot-forming.

12. A process as set forth in claim 11 in which said part of said guiding rolls is pivotally adjusted.

References Cited UNITED STATES PATENTS 2,057,580 10/1936 Layton 72-224 2,008,626 7/1935 Murakami 2257 3,147,521 9/1964 Boehm 2257 3,209,452 10/1965 Schneckenburger 2257 3,374,826 3/1968 Black 164-282 X FOREIGN PATENTS 517,838 3/1955 Italy. 1,323,948 3/1963 France. 1,335,289 7/1963 France.

I. SPENCER OVERHOLSER, Primary Examiner ROBERT D. BALDWIN, Assistant Examiner US. Cl. X.R. 

